1 /*

     2  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)

     3  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.

     4  *

     5  * This library is free software; you can redistribute it and/or

     6  * modify it under the terms of the GNU Library General Public

     7  * License as published by the Free Software Foundation; either

     8  * version 2 of the License, or (at your option) any later version.

     9  *

    10  * This library is distributed in the hope that it will be useful,

    11  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    13  * Library General Public License for more details.

    14  *

    15  * You should have received a copy of the GNU Library General Public License

    16  * along with this library; see the file COPYING.LIB.  If not, write to

    17  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,

    18  * Boston, MA 02110-1301, USA.

    19  *

    20 */

    21 

    22 #ifndef CounterNode_h

    23 #define CounterNode_h

    24 

    25 #include <wtf/Noncopyable.h>

    26 

    27 // This implements a counter tree that is used for finding parents in counters() lookup,

    28 // and for propagating count changes when nodes are added or removed.

    29 

    30 // Parents represent unique counters and their scope, which are created either explicitly

    31 // by "counter-reset" style rules or implicitly by referring to a counter that is not in scope.

    32 // Such nodes are tagged as "reset" nodes, although they are not all due to "counter-reset".

    33 

    34 // Not that render tree children are often counter tree siblings due to counter scoping rules.

    35 

    36 namespace WebCore {

    37 

    38 class RenderObject;

    39 

    40 class CounterNode : Noncopyable {

    41 public:

    42     CounterNode(RenderObject*, bool isReset, int value);

    43 

    44     bool isReset() const { return m_isReset; }

    45     int value() const { return m_value; }

    46     int countInParent() const { return m_countInParent; }

    47     RenderObject* renderer() const { return m_renderer; }

    48 

    49     CounterNode* parent() const { return m_parent; }

    50     CounterNode* previousSibling() const { return m_previousSibling; }

    51     CounterNode* nextSibling() const { return m_nextSibling; }

    52     CounterNode* firstChild() const { return m_firstChild; }

    53     CounterNode* lastChild() const { return m_lastChild; }

    54 

    55     void insertAfter(CounterNode* newChild, CounterNode* beforeChild);

    56     void removeChild(CounterNode*);

    57 

    58 private:

    59     int computeCountInParent() const;

    60     void recount();

    61 

    62     bool m_isReset;

    63     int m_value;

    64     int m_countInParent;

    65     RenderObject* m_renderer;

    66 

    67     CounterNode* m_parent;

    68     CounterNode* m_previousSibling;

    69     CounterNode* m_nextSibling;

    70     CounterNode* m_firstChild;

    71     CounterNode* m_lastChild;

    72 };

    73 

    74 } // namespace WebCore

    75 

    76 #ifndef NDEBUG

    77 // Outside the WebCore namespace for ease of invocation from gdb.

    78 void showTree(const WebCore::CounterNode*);

    79 #endif

    80 

    81 #endif // CounterNode_h